Deep Well Advice

[LC Well]

I've read everything I could find in this forum about deep wells and my contractor obtained the first bid for drilling a well on my property and I'm thinking maybe it is overkill, but wanted to get some additional opinions from people who know far more about wells than I do. This is our first well drilling experience and it will be for domestic water for a 3 Br, 3 Ba, single family home with very limited landscaping. We are siting on a view lot overlooking a giant lake and our elevation is about 550' above the lake level...where all the neighboring property owners hit water. We expect to have a 6" well to a depth of 700' with a static level of about 570'.

Does a 3 hp, 3 phase, 10SDQP3.ON4 for $6400, a H2P80 for $1769 with 1-1/4 galv. drop pipe at $4,160 for a total pump cost of $18,500 seem like overkill for my house? I will be getting additional bids, but I want to compare apples to apples and make sure they are bidding the correct equipment for my house.

 

[Reach4]

You may be better off with a conventional single phase 3-wire pump. Less to go wrong. Subdrive systems have electronics with a lot of points of failure. 10 gpm 3 hp looks about right.

They could run pvc pipe that length I think. It does not rust.

I suspect that price for the pressure tank includes labor, but maybe not.

 

[Sponsor]

 

[LC Well]

Thanks for the comments Reach4, the labor was a separate charge of $1,600 to connect up the pump. The thing that got me questioning this was another post about a well of similar depth where a Goulds 7GS20 pump was recommended and it is about 1/3 the price with a 2hp, 1 phase, 3 wire motor that would supposedly put out about 7 gpm at 700'. If the extra money is worth it to get up to 10 gpm at 60 psi, then I would step up to the price, but this well will represent about 10% of our construction budget so I'd like an adequate supply for our house but I'd like to keep the well cost under $40k if possible and I don't think we can do it with $18,250 in the pump and tank alone.

 

[Reach4]

Look at the pump curves. At 600 ft, the 7 gpm 2 hp pump would put out about 5.8 gpm at 40 psi. That is probably enough gpm for a house, but for a big house, I think many would want the bigger pump.

It's not the (10 gpm 3 hp) vs (7 gpm 2 hp) that is driving majority of the price difference. A lot of the price is tied up in the Subdrive stuff. I expect a Goulds 10GS30 is not priced all that differently than a Goulds 7GS20.

Assuming a 40/60 pressure switch, (10 gpm 3 hp) would supply about 9.7 gpm and (7 gpm 2 hp) would supply about 6.7 gpm -- which is plenty for most houses.

Also understand that equipment like this is marked up around 100%, but the installation price may be less than it ought to be. Plus the markup covers a lot of handling and the possibility of handling warranty swap-outs.

 

[LC Well]

Reach4, thanks so much for taking the time to explain this...I am clearly out of my league but wanting to understand what I am buying and why so I can make a good decision on my $50k+ investment.

So if I'm understanding you correctly, I was probably spec'd the correct HP/gpm of pump for the application, but I might be better off asking about going with a conventional single phase 3-wire pump like a Guilds 7GS30 to see what it does to overall pricing. What I was quoted was for a subdrive constant pressure VFD pump motor which has some desirable features but more complicated electronics which could fail and is more expensive overall. Is that a reasonable laypersons explanation of my situation?

 

[Reach4]

I am not a pro, but yes.

Can you follow the tables? Either pump is reasonable.

 

[Bannerman]

Before committing to any pump or pressure tank, you may want to discuss your application with Cary 'Valveman' Austin who is a moderator on this forum who is normally here during week days. He designed and manufactures a device called Cycle Stop Valve that will supply constant pressure and prevent cycling and extend the lifespan of a conventional well pump.

Probably a waste of time asking your current well guy about a CSV as most are not aware. A CSV will cost a fraction of the price of a VFD and will likely outlive several VFDs.

 

[Valveman]

Thanks Bannerman! Actually most pump installers are aware of the CSV, as it has been around for nearly 30 years now. However, many pump installers are negative about the CSV BECAUSE it cost a fraction of the price and makes the pump last much longer than any VFD.

Even though this is a very deep well it can be done with a CSV1A, because the static level is 570'. Either the 7GS20 or the 10GS30 will work. The 7GS20 will deliver about 6 GPM at pressure, which should be enough for your house. The 10GS30 will deliver about 11 GPM, which is certainly plenty for the house. With either of these pumps I would use the PK1ALT constant pressure control kit for $320.00, and add a 20 gallon size tank purchased locally for less than $200. For $520 dollars the PK1A kit will do a much better job than an expensive and short lived VFD.

I found a 7GS20 on line for $1505.00 and a 10GS30 for $1945.00, which includes the control boxes. Add to this the $520 for the PK1A kit and tank, then all you need is drop pipe, wire, and a few miscellaneous parts. This will cost a fraction of the cost of the VFD controlled pump and will last several times longer.

https://cyclestopvalves.com/pages/reviews

 

[LC Well]

Thanks so much for the information and guidance. This knowledge will help with tremendously when I meet with the driller to look at various options to try to bring the cost down and still get a system that will still perform well.

 

[2stupid2fixit]

Thanks so much for the information and guidance. This knowledge will help with tremendously when I meet with the driller to look at various options to try to bring the cost down and still get a system that will still perform well.

Pay attention to what Cary says about VFD pumps elsewhere in this forum.
IF the driller sells pump replacements as most do, be forewarned that the driller might be allergic to the mention of a CSV. Installing a CSV is sort of like telling a lamp installer that you will never need to call them for a replacement lightbulb and most well drillers are aware that replacing pumps is guaranteed income. Be strong.